blk-throttle: fix potential NULL pointer dereference in throtl_select_dispatch
From: Joseph Qi <hidden>
Date: 2017-08-10 01:22:48
Subsystem:
block layer, control group - block io controller (blkio), the rest · Maintainers:
Jens Axboe, Tejun Heo, Josef Bacik, Linus Torvalds
From: Joseph Qi <redacted> Since throtl_rb_first may return NULL, so it should check tg first and then use it. Signed-off-by: Joseph Qi <redacted> --- block/blk-throttle.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index a7285bf..c1d2c5b 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c@@ -1201,7 +1201,7 @@ static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) while (1) { struct throtl_grp *tg = throtl_rb_first(parent_sq); - struct throtl_service_queue *sq = &tg->service_queue; + struct throtl_service_queue *sq; if (!tg) break;
@@ -1213,6 +1213,7 @@ static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) nr_disp += throtl_dispatch_tg(tg); + sq = &tg->service_queue; if (sq->nr_queued[0] || sq->nr_queued[1]) tg_update_disptime(tg);
--
1.9.4